Canon PowerShot S120 Manual (en)

You can gather selected images together in Collection folders for 
viewing, comparison and editing.
You can gather images from several folders as well as from a single 
folder, allowing you to work with them efficiently.
Click [+ Add collection] in the [Collection] area in the 
main window.
A new collection folder is created in the [Collection] area.
Enter a name for the collection folder.
To create additional collection folders, repeat the operation. Up to 
20 folders can be created.
Select the [File] Menu  [Select collection], and 
select a collection folder to gather images from the 
collection folder names displayed.
Gathering and Editing Images in the Collection Window
Select images or image folders in the main window. 
Select the [File] menu 
 [Add to collection].
The images are added to the selected collection folder, and the 
number of selected images in the collection folder is displayed. 
When an image set to single-image display 
 is added, the 
number of images is indicated as two images.
You can also add images to a collection folder by selecting 
images and folders and then selecting [Add to collection] from 
the menu that appears when you holding down the <control> key.
Select a collection folder in the [Collection] area.
Images in the selected folder are displayed.